The rigs used to drill many oil and/or gas wells currently enjoy much smaller footprints than oil and/or gas wells of the past. Technology, such as coiled tubing operations, has led to a decrease in the space required to perform drilling and/or completion operations on oil or gas wells and a decrease in the time required to prepare for and to perform such operations.
Coiled tubing operations includes coiled tubing drilling, where downhole mud motors turn the bit to deepen a borehole. Coiled tubing drilling is useful in applications such as drilling slimmer wells and for areas where a small rig footprint is essential. In addition, coiled tubing operations are used in reentering wells and drilling underbalanced.
In underbalanced drilling, the amount of pressure (or force per unit area) exerted on a formation exposed in a borehole is less than the internal fluid pressure of that formation. If sufficient porosity and permeability exist, formation fluids enter the borehole.
Other coiled tubing operations involve coiled tubing services. Such services may include fracturing and completions to enhance the overall production of a well. Hydraulic fracturing is a stimulation treatment performed on oil and gas wells in low-permeability reservoirs. Specially engineered fluids are pumped into the portion of the reservoir to be treated at a high pressure and rate, causing a vertical fracture to open. Proppant, such as grains of sand of a particular size, is mixed with the treatment fluid to keep the fracture open when the treatment is complete.
In addition to coiled tubing operations, traditional drillpipe operations have seen reductions in the area required to accommodate the equipment associated with drilling, completions, and production of a well. This is particularly true for offshore rigs where floor space is easily quantified.
As the space required for a drilling rig has decreased, the need has arisen for space allocated to various pieces of equipment and systems to also decrease. Further, the decrease in available space and time has accentuated the need for decreasing the footprint and preparation time for pressure control equipment and drilling waste management equipment as well as other associated equipment.
Using conventional drilling methods, the time required to position and assemble pressure control and drilling waste management equipment often requires days and available space to rig up. The time required to prepare the drilling equipment is typically days as well. To reduce overall costs associated with drilling an oil and/or gas well, there is a need to reduce the time and space required to position and assemble the pressure control and drilling waste management equipment in order to reduce the overall time to prepare a site for drilling. There is also a need to reduce the overall weight of the equipment to meet lift requirements. All of these needs must be met while continuing to maintain precise pressure controls, fluids processing efficiency, and drilling waste management in a closed loop process.
Another result of technological improvements in the field of drilling oil and gas wells is that there is less downtime and environmental impact during the actual drilling operation. Thus, the equipment used to provide pressure control and prepare the borehole fluid for reuse must be able to work nearly continuously in a closed loop design to promote zero discharge into the environment during the drilling operation. Proper equipment selection and placement is necessary to ensure continual operation without requiring additional space.